Turbodrill with rubber rotor bearings

Abstract

A turbodrill which is connected to a string of drill pipe as a rotating shaft for driving a drill bit which may be a rotary bit or a high speed solid head diamond bit. The turbine section has rotor and stator blades which are cresent shaped in cross section with each blade having an exit angle of 14°-23° for maximum turbine efficiency. The bearing shaft is provided with chevron rotary seals positioned below the rotary bearings carrying both radial and vertical thrust. Fluid lubricant fills the space from the rotary seals to a predetermined level above the bearings. A piston seals the lubricant chamber and is pressurized by drilling fluid (i.e. mud) flowing through the tool. A layer of lubricant fluid overlies the first piston and has a second piston covering said fluid and transmitting pressure from the drilling fluid to the lubricant fluid surrounding the bearings. Rubber friction bearings which are cooled and lubricated by flow of drilling mud are provided between the rotor and stator bearing surfaces which provide for extended rotor bearing life and cushion the radial thrust bearings against radial shock and provide for a substantially extended life for the radial thrust bearings.

I claim: 
     
       1. A turbodrill adapted for connection at one end to the lower end of a drill string and at the other end to a drill bit to be driven thereby, comprising a tubular housing having an upper stator portion and a lower bearing portion,   a stator comprising a plurality of fixed stator members in said stator portion,   said fixed stator members each comprising an outer and inner sleeve member with a stator blade extending radially therebetween,   a rotor shaft extending through said stator portion,   a plurality of rotor members, each comprising a sleeve member supported in a fixed position on said rotor shaft and having a turbine blade extending radially therefrom,   said turbine blades being cooperable with said stator blades whereby the flow of drilling fluid through said turbodrill housing is operable to rotate said rotor shaft,   said rotor sleeve members being supported one in each of said stator inner sleeves in rotary bearing relation therewith and forming a rotary bearing for rotation of said rotor shaft and said turbine blades,   at least one of said sleeve members in each of said rotary bearings having a peripheral recess in the surface thereof and a rubber bearing member supported in each such recess in bearing relation with the other of said sleeve members of such rotary bearing, and   said rubber bearing members each having passages in the bearing surfaces thereof operable to conduct drilling fluid into the space of rotary bearing contact to cool and lubricate the rotary bearing surfaces.   
     
     
       2. A turbodrill according to claim 1 in which said peripheral recesses are in said rotor sleeve members.   
     
     
       3. A turbodrill according to claim 1 in which said peripheral recesses are in said stator inner sleeve members.   
     
     
       4. A turbodrill according to claim 2 in which said rubber bearing passages comprise flats formed in the surfaces thereof and equally spaced around the periphery of the bearing surfaces thereof.   
     
     
       5. A turbodrill according to claim 3 in which said rubber bearing passages comprise longitudinally extending grooves formed in the surfaces thereof.   
     
     
       6. A turbodrill according to claim 1, 2 or 3 in which said rubber bearing members are of Buna N, having a Durometer hardness of about 90, and are molded on said peripheral rotary bearing sleeve member recesses.